Hi.Sample/Disp/DemoDrawing.cs

using Hi.Geom;
using Hi.Disp;
using System.Collections.Generic;
using Hi.Disp.Treat;
using Hi.Coloring;

namespace Sample.Disp
{
    /// <summary>
    /// Demonstrates various drawing techniques using the HiAPI graphics system.
    /// Provides examples of primitive drawing, attribute specification, and rendering options.
    /// Includes methods for drawing lines, points, triangles, and other geometric primitives.
    /// </summary>
    /// <remarks>
    /// ### Source Code
    /// [!code-csharp[SampleCode](~/../Hi.Sample/Disp/DemoDrawing.cs)]
    /// </remarks>
    public static class DemoDrawing
	{
		/// <summary>
		/// Demonstrates simple line drawing using raw vertex coordinates.
		/// Creates a basic line strip from three vertices and displays it using DemoUtil.
		/// </summary>
		public static void FreeDrawing()
		{
			#region DocSite.FreeDrawing
			double[] vs =
				{0,0,0
				,1,0,0
				,0,0,1};
            DemoUtil.Present("EasyDraw"
				, new Drawing(vs, Stamp.V, GL.GL_LINE_STRIP));
			#endregion
		}

		/// <summary>
		/// Demonstrates various types of line drawing techniques.
		/// Shows how to create points, line strips, line strips with normals, and colored line strips.
		/// Illustrates different ways to specify vertex attributes like position, color, and normal.
		/// </summary>
		public static void DrawLines()
		{
			List<Vec3d> ps;
			double[] vs;
			int n = 10; //vertex num

			////create drawPoints
			ps = new List<Vec3d>(n);
			for (int i = 0; i < n; i++)
				ps.Add(new Vec3d(i, 0, 0));
			vs = new double[ps.Count * 3];
			for (int i = 0; i < ps.Count; i++)
			{
				vs[3 * i] = ps[i].x;
				vs[3 * i + 1] = ps[i].y;
				vs[3 * i + 2] = ps[i].z;
			}

			//V means Vertex
			Drawing drawPoints = new Drawing(vs, Stamp.V, GL.GL_POINTS);

			////create drawLineStrip
			vs = new double[ps.Count * 3];
			for (int i = 0; i < ps.Count; i++)
			{
				vs[3 * i] = i;
				vs[3 * i + 1] = 0;
				vs[3 * i + 2] = 1;
			}
			Drawing drawLineStrip = new Drawing(vs, Stamp.V, GL.GL_LINE_STRIP);

			////create drawLineStripWithNormal
			//the content of vs is Nx,Ny,Nz,Vx,Vy,Vz, Nx,Ny,Nz,Vx,Vy,Vz, ...
			vs = new double[n * 6];
			for (int i = 0; i < n; i++)
			{
				//nx,ny,nz
				vs[6 * i] = 1;
				vs[6 * i + 1] = 0;
				vs[6 * i + 2] = 0;
				//x,y,z
				vs[6 * i + 3] = i;
				vs[6 * i + 4] = 0;
				vs[6 * i + 5] = 2;
			}
			//V means Vertex; N means Normal
			Drawing drawLineStripWithNormal =
				new Drawing(vs, Stamp.NV, GL.GL_LINE_STRIP);

			////create drawColorLines
			vs = new double[n * 6];
			for (int i = 0; i < n; i++)
			{
				//the rgb values set casually.
				//r,g,b
				vs[6 * i] = i % 3 / 2D;
				vs[6 * i + 1] = i % 5 / 4D;
				vs[6 * i + 2] = i % 7 / 6D;
				//x,y,z
				vs[6 * i + 3] = i;
				vs[6 * i + 4] = 0;
				vs[6 * i + 5] = 3;
			}
			//V means Vertex; C means Color
			Drawing drawLineStripWithColor = new Drawing(vs, Stamp.CV, GL.GL_LINE_STRIP);

            DemoUtil.Present("DrawLines",
				new DispList(drawPoints, drawLineStrip
				, drawLineStripWithNormal, drawLineStripWithColor));
		}

		/// <summary>
		/// Demonstrates drawing triangles using OpenGL primitives.
		/// Shows how to create colored triangles (CV) and colored triangles with normals (CNV).
		/// Illustrates packing of vertex attributes (color, normal, position) into arrays for rendering.
		/// </summary>
		public static void DrawTrianglesByPrimitives()
		{
			int n = 10;// triangle num
			double[] vs;

			////create drawTrisCV
			//each triangle has 3 point; each point has r,g,b,x,y,z, totally 6 doubles.
			vs = new double[n * 3 * 6];
			for (int i = 0, k = 0; i < n; i++)
			{
				//the rgb values set as casual.
				Vec3d rgb = ColorUtil.GetDiscreteRgb(i);
				Tri3d tri = new Tri3d(new Vec3d(i, 0, 0), new Vec3d(i + 1, 0, 0), new Vec3d(i + 0.5, 0, 1));
				for (int j = 0; j < 3; j++)
				{
					vs[k++] = rgb.x;
					vs[k++] = rgb.y;
					vs[k++] = rgb.z;
					vs[k++] = tri.ps[j].x;
					vs[k++] = tri.ps[j].y;
					vs[k++] = tri.ps[j].z;
				}
			}
			//V means Vertex; C means Color
			Drawing drawTrisCV = new Drawing(vs, Stamp.CV, GL.GL_TRIANGLES);

			////create drawTrisCNV
			/////each triangle has 3 point; each point has r,g,b,nx,ny,nz,x,y,z, totally 6 doubles.
			vs = new double[n * 3 * 9];
			for (int i = 0, k = 0; i < n; i++)
			{
				//the rgb values set as casual.
				Vec3d rgb = ColorUtil.GetDiscreteRgb(i);
				Tri3d tri = new Tri3d(new Vec3d(i, 0, 3), new Vec3d(i + 1, 0, 3), new Vec3d(i + 0.5, 0, 4));
				Vec3d nn = tri.GetNormal();
				for (int j = 0; j < 3; j++)
				{
					vs[k++] = rgb.x;
					vs[k++] = rgb.y;
					vs[k++] = rgb.z;
					vs[k++] = nn.x;
					vs[k++] = nn.y;
					vs[k++] = nn.z;
					vs[k++] = tri.ps[j].x;
					vs[k++] = tri.ps[j].y;
					vs[k++] = tri.ps[j].z;
				}
			}
			//V means Vertex; C means Color; N means Normal
			Drawing drawTrisCNV = new Drawing(vs, Stamp.CNV, GL.GL_TRIANGLES);

            //the color of colorTrisDraw is not influence by outer color setting.
            DemoUtil.Present("DrawTrianglesByPrimitives",
				new DispList(new RgbTreat(1, 0, 0), drawTrisCV, drawTrisCNV));
		}

		/// <summary>
		/// Demonstrates drawing 3D triangles using the Tri3d helper class.
		/// Creates a series of triangles and renders them as both face (filled) and line (wireframe) drawings.
		/// Shows how to apply different colors to faces and lines of the same geometry.
		/// </summary>
		public static void DrawTri3d()
		{
			int n = 10;
			List<Tri3d> tris = new List<Tri3d>(n);
			for (int i = 0; i < n; i++)
				tris.Add(new Tri3d(new Vec3d(i, 0, 0), new Vec3d(i + 1, 0, 0), new Vec3d(i + 0.5, 0, 1)));

			Drawing faceDraw = tris.GetFaceDrawing();
			Drawing linesDraw = tris.ToLineDrawing();

            DemoUtil.Present("DrawTri3d",
				new DispList(new RgbTreat(0, 0, 1), linesDraw
				, new RgbTreat(1, 0, 0), faceDraw));
		}

		static void Main()
		{
			//FreeDrawing();
			//DrawLines();
			//DrawTrianglesByPrimitives();
			DrawTri3d();
		}
	}
}